/*
 *                               POK header
 *
 * The following file is a part of the POK project. Any modification should
 * be made according to the POK licence. You CANNOT use this file or a part
 * of a file for your own project.
 *
 * For more information on the POK licence, please see our LICENCE FILE
 *
 * Please follow the coding guidelines described in doc/CODING_GUIDELINES
 *
 *                                      Copyright (c) 2007-2021 POK team
 */

/* @(#)s_ceil.c 5.1 93/09/24 */
/*
 * ====================================================
 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
 *
 * Developed at SunPro, a Sun Microsystems, Inc. business.
 * Permission to use, copy, modify, and distribute this
 * software is freely granted, provided that this notice
 * is preserved.
 * ====================================================
 */

/*
 * ceil(x)
 * Return x rounded toward -inf to integral value
 * Method:
 *	Bit twiddling.
 * Exception:
 *	Inexact flag raised if x not equal to ceil(x).
 */

#ifdef POK_NEEDS_LIBMATH

#include "math_private.h"
#include <libm.h>

static const double huge = 1.0e300;

double ceil(double x) {
  int32_t i0, i1, jj0;
  uint32_t i, j;
  EXTRACT_WORDS(i0, i1, x);
  jj0 = ((i0 >> 20) & 0x7ff) - 0x3ff;
  if (jj0 < 20) {
    if (jj0 < 0) {          /* raise inexact if x != 0 */
      if (huge + x > 0.0) { /* return 0*sign(x) if |x|<1 */
        if (i0 < 0) {
          i0 = 0x80000000;
          i1 = 0;
        } else if ((i0 | i1) != 0) {
          i0 = 0x3ff00000;
          i1 = 0;
        }
      }
    } else {
      i = (0x000fffff) >> jj0;
      if (((i0 & i) | i1) == 0)
        return x;           /* x is integral */
      if (huge + x > 0.0) { /* raise inexact flag */
        if (i0 > 0)
          i0 += (0x00100000) >> jj0;
        i0 &= (~i);
        i1 = 0;
      }
    }
  } else if (jj0 > 51) {
    if (jj0 == 0x400)
      return x + x; /* inf or NaN */
    else
      return x; /* x is integral */
  } else {
    i = ((uint32_t)(0xffffffff)) >> (jj0 - 20);
    if ((i1 & i) == 0)
      return x;           /* x is integral */
    if (huge + x > 0.0) { /* raise inexact flag */
      if (i0 > 0) {
        if (jj0 == 20)
          i0 += 1;
        else {
          j = i1 + (1 << (52 - jj0));
          if (j < (uint32_t)i1)
            i0 += 1; /* got a carry */
          i1 = j;
        }
      }
      i1 &= (~i);
    }
  }
  INSERT_WORDS(x, i0, i1);
  return x;
}

#endif
